A moth called the Tomato Leaf Miner, or Tuta Absoluta, has ravaged 80% of tomato farms, Commissioner of Agriculture Daniel Manzo Maigar said.
He said 200 farmers together lost at least 1bn naira ($5.1m; Ј3.5m) over the past month.
The price of a basket of tomatoes has increased from $1.20 less than three months ago to more than $40 today.
In Nigeria, officials declare a state of emergency to indicate they are taking drastic action to deal with a problem, the BBC's Muhammad Kabir Muhammad says.
In this case the state sent government agricultural officials to Kenya to meet experts on the Tomato Leaf Miner to learn how to deal with the pest.
Kaduna is in the north of the country, where according to the UN most tomato production takes place,
A tomato paste manufacturing business in northern Kano state owned by Africa's richest man, Aliko Dangote, suspended production earlier in the month due to the lack of tomatoes, reports Forbes.
Tomatoes are a basic part of most Nigerians' diets and the word tomato has trended on Twitter as people discuss the rising price.
One of the memes being shared is a tongue-in-cheek look at Nigerian pain over discovering the annual festival in Spain where people throw tomatoes at each other.